Initial Burden for Grid-Scale Storage Batteries to Increase: Over 50% Paid Upfront?

BESS NEWS, a specialized news site that freely publishes important information on grid-scale storage batteries, has released an explanatory article titled "Will the initial cash for grid-scale storage batteries become heavier? ~OCCTO's new rules mean a 10% guarantee deposit and over 50% initial payment~" which organizes the practical impact on BESS projects of new operations concerning grid access procedures for grid-scale storage batteries announced by OCCTO (Organization for Cross-regional Coordination of Transmission Operators). Under these new rules, for contract applications for grid-scale storage batteries received by general transmission and distribution operators or distribution operators on or after April 1, 2026, a guarantee deposit of 10% of the estimated construction cost burden will be applied. Furthermore, even when construction costs are paid in installments, it is explicitly stated that for grid-scale storage batteries, the initial payment amount will, in principle, be 50% or more of the total construction cost burden. This is not a system intended to halt the grid-scale storage battery business itself. However, it is an important change that could increase the cash required before interconnection, the so-called "initial cash," potentially affecting BESS project financing plans, loan disbursement timings, and investment decisions. BESS NEWS organizes this change not merely as a procedural alteration, but as a practical theme related to the development, investment, and financing of grid-scale storage batteries.

Table of Contents

- Themes Explained by BESS NEWS - 1-1. New Rules for Grid-Scale Storage Batteries Announced by OCCTO - 1-2. What a 10% Guarantee Deposit and Over 50% Initial Payment Mean

- Key Changes to Note for BESS Projects - 2-1. Guarantee Deposit at Contract Application Becomes 10% - 2-2. Over 50% Initial Payment Required Even for Installment Payments of Construction Costs

- Practical Cautions Easily Misunderstood - 3-1. Installment Payments are Not Prohibited - 3-2. The "Reception Date" Not "Submission Date" is the Standard - 3-3. Guarantee Deposit and Initial Payment of Construction Costs are Managed Separately

1. Themes Explained by BESS NEWS

This BESS NEWS article focuses on the increase in the guarantee deposit for contract applications for grid-scale storage batteries and the stricter installment payment rules for construction costs, updated and announced by OCCTO on March 18, 2026. The target projects are grid-scale storage battery projects for which general transmission and distribution operators or distribution operators receive contract applications on or after April 1, 2026. BESS NEWS organizes this change not merely as a system explanation of "guarantee deposits will increase" or "initial payments will rise," but from a practical perspective, addressing "how it affects project cash flow," "how to manage application timing," and "what to factor into investment decisions." Particularly for BESS projects, many expenditures occur before operation starts, including land, development costs, equipment orders, EPC contracts, and grid interconnection-related fees. This rule change potentially increases the initial cash related to grid access among these costs.

2. Key Changes to Note for BESS Projects

The first notable change is the guarantee deposit at the time of contract application. According to OCCTO's categorization, for regular power generation facility contract applications, the guarantee deposit is 5% of the estimated construction cost burden. In contrast, for grid-scale storage batteries, it will be treated as 10% of the estimated construction cost burden. For example, in projects with a large estimated construction cost burden, even the guarantee deposit alone could represent a significant financial burden. This directly impacts the initial financial planning of BESS projects.

Another significant change concerns installment payments for construction costs. Construction costs are the expenses borne by the connecting business operator for the necessary construction to connect to the grid. For grid-scale storage batteries, it has now been explicitly stated that even when making installment payments, the initial payment amount must be 50% or more of the total construction cost burden. This means that even if installment payments are possible, the first payment may not necessarily be small. The main body of the BESS NEWS article explains the necessity of checking this "10% guarantee deposit" and "over 50% initial payment" not separately, but within the same cash flow statement.

3. Practical Cautions Easily Misunderstood

A common misconception with this change is the view that "if installment payments are possible, the initial burden is light." In reality, for grid-scale storage batteries, even when construction costs are paid in installments, the initial payment amount is, in principle, indicated to be 50% or more of the total. Therefore, even with installment payments, a large amount of initial capital may be required.

Another important point is the application criteria. These new rules apply to projects for which general transmission and distribution operators or distribution operators receive contract applications on or after April 1, 2026. It cannot be judged solely by the company's internal decision date, the date the application form was created, or the date it was sent. Specifically, for projects planning to apply from late March to early April 2026, there is a possibility of becoming subject to the new rules due to incomplete documentation or delays in reception confirmation.

Also, the guarantee deposit and the initial payment of construction costs